40 mm Bofors AA guns made in GB and US

Richard Suggitt · #1 05-09-18, 13:01

Nor have we worked out what these two controls are. Each knob can turn three times, each has two opposing scales. It feels as if it's some sort of coarse setting for the sights, but we have not been able to set them in such a way that the sights exactly match the barrel.

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Just for completeness, this is a closeup of the actual sights. We know that the items that look like boxes are the night sights.

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As I said earlier, any information will be gratefully received ! Many thanks in anticipation !!

notenoughtoys · #2 06-09-18, 02:58

Richard I have found my copy of a small Finnish manual I have and it is listing that lower dial as a "pysyttimen 7". Google translate is not finding this word so hopefully someone will chime in and translate. I believe the two upper knobs are for zeroing the sights and may not line up exactly with the barrel due to minimum range and bullet drop ??
If you can post your email I will scan in all relevant pages in my manual and send them to you in a zipped file.

Richard Suggitt · #3 09-09-18, 21:26

Quote:

Originally Posted by notenoughtoys

Richard I have found my copy of a small Finnish manual I have and it is listing that lower dial as a "pysyttimen 7". Google translate is not finding this word so hopefully someone will chime in and translate. I believe the two upper knobs are for zeroing the sights and may not line up exactly with the barrel due to minimum range and bullet drop ??
If you can post your email I will scan in all relevant pages in my manual and send them to you in a zipped file.

Many thanks for responding ! I'll pm you my address.

Richard Suggitt · #4 09-09-18, 22:19

Quote:

Originally Posted by notenoughtoys

Richard I have found my copy of a small Finnish manual I have and it is listing that lower dial as a "pysyttimen 7". Google translate is not finding this word so hopefully someone will chime in and translate. I believe the two upper knobs are for zeroing the sights and may not line up exactly with the barrel due to minimum range and bullet drop ??
If you can post your email I will scan in all relevant pages in my manual and send them to you in a zipped file.

Like you I cant find a translator that will give me the English for "pysyttimen ", but I've googled the word and it crops up in a number of different contexts.... I suspect it could mean something like 'illustration', 'assembly', 'part number' or suchlike.

Richard Suggitt · #5 12-09-18, 16:38

Quote:

Originally Posted by Richard Suggitt

Just for completeness, this is a closeup of the actual sights. We know that the items that look like boxes are the night sights.
Attachment 102017

Slight picky update.... the sights are not specifically night sights. They seem to have been made by a company called AGA-BALTIC and are more properly called Reflector Sights or Reflex Sights. They can be used at night but also have drop-down filters so they can be used in the daytime.

notenoughtoys · #6 12-09-18, 18:22

Scans sent - if you need any other details please let me know. Still looking for one more reference book (no luck yet) so I will email you if it ever shows up !

Richard Suggitt · #7 14-09-18, 12:35

Quote:

Originally Posted by notenoughtoys

Scans sent - if you need any other details please let me know. Still looking for one more reference book (no luck yet) so I will email you if it ever shows up !

Many many thanks for those scans... I'm still digging into them. As far as I can tell, the diagram that shows the dial in question is actually a lubrication diagram. I had to get some help with the translation, but the word 'pysyttimen' seems to mean 'support bracked' or 'retaining bracket', so its not about the function of the actual dial. However, the exploded views of the calculator and sights are very interesting.

I plan to visit one of the museums in London soon to see what manuals they have in the archives for the Bofors gun, so I'll hold off asking for further help on this forum for a while.

Thanks again!
Richard

Richard Suggitt · #8 21-09-18, 18:50

Quote:

Originally Posted by notenoughtoys

Scans sent - if you need any other details please let me know. Still looking for one more reference book (no luck yet) so I will email you if it ever shows up !

Hi ! We've been working on the material you kindly sent me, it's been very interesting ! Can I ask for another favour though ?

In the scan of the Finnish manual that has exploded diagrams of the corrector and sights on pages numbered 34 and 35, there are lines leading to a set of 'U' numbers... ie U1 to about U48. Is there a key where these 'U' numbers (presumably part or component numbers) are listed and described; if so, would it be possible to get a scan of that please ?

Thanks in anticipation
Richard

Richard Suggitt · #9 17-10-18, 16:10

On another tack.... we've been looking at the electrical wiring that is on our Bofors. A lot of it is for lighting; this is run off a 6v battery and the wiring and connectors are all (naturally) low current. We can trace the wiring runs pretty well.

However..... there are some items we are not sure about. There are a couple of heavy-duty pin sockets just to the left of the ejection chute; one has a lead that goes into the centre of the revolve drum, and another lead that goes to a pretty chunky brass brass socket that is positioned just left of the ejection chute. All this is totally separate from the lighting wiring, and we have no idea what it is all for. It looks like you would plug a power supply into one part of this, and some device that needs power into the other; we have no idea why one lead goes into the revolve drum, as it is inacessible and has not electrical brushes on it. The gun is all manual.... no electric motors anywhere. I'll post some photos below. Any ideas anyone.... ?

Incidentally, from info in the Terry Gander book we now believe that 'our' gun was made in Poland in about 1942 (but to the 1938 design) and was shipped to Portugal.

Richard Suggitt · #10 11-12-18, 18:21

On another tack.... someone mentioned that the Corrector had a habit of turning as the gun traverses. Ours does the same.... we are now pretty sure we know why this happens, and that it is deliberate. If anyone is interested let me know, I'm happy to explain.

Richard Suggitt · #11 20-12-18, 15:09

Another new question... we have to replace or retemper the set of balance springs that support the weight of the barrel when it is elevated. [They are housed in the two cylinders that sit below the barrel]. Unfortunately, we dont know how 'springy' the springs should be. I gather this is expressed in engineering terms as the 'spring rate' and is the weight required to compress the springs by one inch.

Does anyone have any technical info about the characteristics of these springs, especially the spring rate value ?